Weathering your home energy costs

Sealing gaps can trim bills

When you close a window or door, you may think you’re shutting out the elements. But unless something seals the door or window at the edges, it can leak a considerable amount of air. Weatherstripping provides that seal.

Some weatherstripping is installed permanently with nails or screws. Others are self-adhesive and can be easily applied and removed. Temporary installation makes sense if you don’t need a certain product year-round, or if you are renting a home.

Here is what’s available:

Temporary relief

¢ Foam and felt strips come in rolls with peel-off adhesive and can be cut to length with scissors. Felt is not the most effective or durable of weatherstripping materials, but it is inexpensive and easy to install. Foam also is easy to install and inexpensive, but has low durability.

¢ Tubular rubber and vinyl strips are usually self-adhesive, although some have a flange through which you drive staples or small nails. They’re best for use on doors and provide an effective air barrier. Expect to pay more for tubular rubber and vinyl strips.

¢ Vinyl tension strips look like long V-shaped hinges. Installed on double-hung windows or the tops and sides of doors, V-strips fold when a door or window is closed and flex to fit tightly against the other side of the opening. Durable and easy to install, V-strips may slightly impede operation of doors or windows. They’re also moderately expensive.

¢ Metal strips come both as V-strips and as flatter, single-layer pieces. Both types tack in place.

Long-term fixes

Caulk, foam and putty typically are used to make long-term seals for holes that were made intentionally – such as those for electrical, plumbing and ventilation systems – as well as cracks that have opened up over time. Silicone caulks and silicone-modified polymer caulks are weatherproof, long lasting and have good flexibility. Latex caulks are easier to apply than silicone caulks, but they should be protected with paint if used outdoors. Rope caulk, meanwhile, is a preformed puttylike cord that can be removed.

Foams come in strips (called “backer rods”) used to fill cracks wider than 3/8-inch and deeper than 1/2-inch prior to caulking, and in a aerosol form that is squirted out like whipped cream. There are two types of aerosol foam: Polyurethane expands so dramatically that it can distort windows and doorjambs if injected into voids between the frame and the structural rough opening; latex foam expands less, is somewhat easier to control and much easier to clean up.

Caulking and weatherstripping can be expected to pay for themselves in just one year, according to the Department of Energy. The exact savings will depend on the cost of the job, the amount of energy you’ve saved and the current cost of the energy you use.